Trailer Brakes Work Intermittently on a Trailer Towed by a 1998 Ford F-150

Published 09/21/2011

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Digital Multimeter with 42" Long Test Leads - LED Display

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Question:

I have a 98 F-150 with factory tow package. I am using a Tekonsha Voyager brake control my problem is during a recent trip I encountered an intermittent problem of aplying the brakes and having no trailer brakes even though the led on the Voyager turned amber then about half way to a stop suddenly the trailer brakes will lockup. even when the controller is turned way down, when this happens it scares the bejeezes out of you when the brakes kick in. The really odd thing is that you may go 75 miles with numerous stops without any problem, then when you are trying to stop at the bottom of an interstate ramp bang! the problem returns. I already changed out the vehicle receptacle to no avail I also checked the connections at the trailer wheels. this also happenes when using the manual override slider. Ive heard from another RVer that a bare wire inside the trailer hub could be the culprit but I havent got into it yet what do you think?

asked by: John C

Expert Reply:

It sounds to me like either there is a bad connection with the brake controller and/or wiring, or the brake magnets themselves need to be replaced. There are a couple of ways that you can check the brake controller and wiring.

First, to make sure the brake controller is putting out power like it is supposed to, use a circuit tester like # PTW2993 if needed to test the wiring on the back of the controller. When you apply the brakes or manual override, there should be a constant amount of power sent along the blue wire depending on what level you have the controller set to.

If it does not seem like it is sending the right amount of power or fluctuates from little power to a lot of power, there could be a problem with the internal circuitry of the brake controller, and it will need to be replaced.

You will also want to make sure you have good ground connections at the vehicle and trailer side connectors and at the brake magnets. A bad ground connection could cause or at least lend to the problem you are having. The grounds should all be connected to clean and corrosion free bare metal surfaces.

Finally, check the brake magnets. Start with a visual inspection of the magnets. If you can see windings coming through, then the magnets will need to be replaced. Further testing of the magnets will require a multimeter, like # PT89ZR if needed, and a separate 12-volt battery. I have included a link to an FAQ article that explains how to test the magnets and what to look for.

expert reply by: Michael H